[Scruff]

My two front tyres are different to my two back tyres but all seem to have an equal amount of tread. One of my fronts has a chunk taken out of the sidewall which is fairly deep (was like it when i bought it guv) so i really need to replace it. Would i do well to just buy a new set all round?
To be honest, the tyres on there are pretty crap when it comes to grip and i've never known a 4wd car to be so slidey.